<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
    body {
      margin: 0px;
    }

    #ancestor {
     position: absolute;
     width: 100px;
     height: 100px;
     border-radius: 5px;
     overflow: hidden;
    }

    iframe {
      position: absolute;
      width: 200px;
      height: 200px;
      border: none;
      opacity: 0.5;
    }
    </style>
  </head>
  <body>
    <div id="ancestor">
      <iframe src="/cross-site/baz.com/title1.html"></iframe>
    </div>
  </body>
</html>
